Five former members of David Cameron 's cabinet are among dozens of ex-Coalition ministers earning up to £600 an hour in the sector they used to regulate.

The Prime Minister faces calls for a tougher crackdown on the Whitehall gravy train after a Mirror investigation revealed at least 25 former government bigwigs are raking in well over £1million between them in relevant industries.

Many are trousering thousands of pounds a day in plum part-time roles as directors, advisers or board chairmen.

But it highlights how a trumpeted Tory move to stop ministers cashing in after leaving office has barely slowed the revolving door from Whitehall to big business.

New job: Former Health Secretary Andrew Lansley (Photo: Getty)

Labour MP Paul Flynn said: "It is wrong that anyone should be selling their inside knowledge and contacts.

"It used to be that a Ministerial post was the pinnacle of any career.

"Now it seems to be a stepping stone to retirement riches."

Ex-Health Secretary Andrew Lansley, former Energy Secretaries Chris Huhne and Ed Davey, ex- Northern Ireland and Environment Secretary Owen Paterson and former Schools Minister David Laws all now work for firms linked to the areas they were previously paid to oversee.

There is no suggestion they have broken any rules.

(Photo: Getty)

Seven of the 25 ministers – including Tory Mr Paterson – are still MPs while two more, including Lord Lansley, were handed peerages last summer and are now in the House of Lords.

Former Water Minister Richard Benyon, already one of Parliament’s wealthiest Members of Parliament, is now a £1,000-a-day part-time chairman of the UK Water Partnership.

He said: "There is no conflict between my role as Minister and this appointment."

His successor as Minister for Water, ex-Lib Dem MP Dan Rogerson, recently landed an estimated £3,500-a-day part-time role with the Wessex Water Partnership.

Documents show the panel that interviewed him for the job was chaired by David Heath, another former Lib Dem minister from the same department, who now earns £40,000 a year working part-time for the Consumer Council for Water.

(Photo: PA)

Also on the list is 10-job Tory Mark Simmonds, whose well-paid appointments since quitting as Africa Minister include roles with three firms he had meetings with during his time in Whitehall.

Another former Africa Minister, Sir Henry Bellingham – knighted by the PM last month – earns £4,000 a month for seven hours’ work with a mining firm he once lobbied for while in Government.

Four of Mr Cameron’s former Energy Ministers now work for energy firms they used to regulate, including Mr Huhne and Mr Davey.

Mr Davey – already chairman of Mongoose energy – last week announced he has landed a second role advising MHP Communications, a PR firm that counts EDF Energy among its clients.

He joins Lib Dem pal Paul Burstow – a former Health Minister – who is already working for MHP’s health practice.

(Photo: PA)

(Photo: AFP)

Former Pensions Minister Steve Webb is now head of policy for pensions giant Royal London.

Ex-Treasury Minister Mark Hoban is a director at the London Stock Exchange.

And former Middle East Minister Sir Hugh Robertson now works for a PR firm representing the Dubai Government.

Before he came to power in 2010, Mr Cameron vowed a crackdown on ex-ministers using contacts and information, gained in office, for private gain.

(Photo: PA)

Steve Webb: He also has a new job (Photo: PA)

But his only significant move has been to double from one to two years the time during which ex-Ministers must not directly lobby the Government on behalf of industry.

Questions are now being asked about the effectiveness of the Advisory Committee on Business Appointments which regulates ex-Ministers’ new jobs.

Ministers must apply to the committee if they want to take up a job within two years of leaving office.

Acoba meets in private to discuss each appointment but has waved them all through with little or no complaint.